BACKGROUND Overconsumption of energy from food is a major contributor to the high rates of overweight and obesity in many populations. There is growing evidence that interventions that target the food environment may be effective at reducing energy intake. The current study aimed to estimate the effect of decreasing the proportion of higher energy (kcal) foods, with and without reducing portion size, on energy purchased in worksite cafeterias. METHODS AND FINDINGS This stepped-wedge randomised controlled trial (RCT) evaluated 2 interventions: (i) availability: replacing higher energy products with lower energy products; and (ii) size: reducing the portion size of higher energy products. A total of 19 cafeterias were randomised to the order in which they introduced the 2 interventions. Availability was implemented first and maintained. Size was added to the availability intervention. Intervention categories included main meals, sides, cold drinks, snacks, and desserts. The study setting was worksite cafeterias located in distribution centres for a major United Kingdom supermarket and lasted for 25 weeks (May to November 2019). These cafeterias were used by 20,327 employees, mainly (96%) in manual occupations. The primary outcome was total energy (kcal) purchased from intervention categories per day. The secondary outcomes were energy (kcal) purchased from nonintervention categories per day, total energy purchased per day, and revenue. Regression models showed an overall reduction in energy purchased from intervention categories of -4.8% (95% CI -7.0% to -2.7%), p < 0.001 during the availability intervention period and a reduction of -11.5% (95% CI -13.7% to -9.3%), p < 0.001 during the availability plus size intervention period, relative to the baseline. There was a reduction in energy purchased of -6.6% (95% CI -7.9% to -5.4%), p < 0.001 during the availability plus size period, relative to availability alone. Study limitations include using energy purchased as the primary outcome (and not energy consumed) and the availability only of transaction-level sales data per site (and not individual-level data). CONCLUSIONS Decreasing the proportion of higher energy foods in cafeterias reduced the energy purchased. Decreasing portion sizes reduced this further. These interventions, particularly in combination, may be effective as part of broader strategies to reduce overconsumption of energy from food in out-of-home settings. TRIAL REGISTRATION ISRCTN registry ISRCTN87225572.

中文翻译：

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减少高能量食品比例和减少份量对工作场所自助餐厅购买食品的影响：一项阶梯楔形随机对照试验。


背景技术来自食物的能量的过度消耗是许多人群中超重和肥胖率高的主要原因。越来越多的证据表明，针对食物环境的干预措施可能有效减少能量摄入。当前的研究旨在评估减少高能量（千卡）食物比例（无论是否减少份量）对工作场所自助餐厅购买能量的影响。方法和结果 这项阶梯式楔形随机对照试验 (RCT) 评估了 2 种干预措施：(i) 可用性：用低能量产品替代高能量产品； (ii) 尺寸：减少高能量产品的份量。共有 19 家自助餐厅按照引入 2 项干预措施的顺序被随机分组​​。首先实施并维护可用性。尺寸被添加到可用性干预中。干预类别包括主餐、配菜、冷饮、小吃和甜点。研究地点是位于英国一家大型超市配送中心的工地自助餐厅，持续了 25 周（2019 年 5 月至 11 月）。这些自助餐厅共有 20,327 名员工使用，其中主要 (96%) 从事体力工作。主要结果是每天从干预类别购买的总能量（千卡）。次要结果是每天从非干预类别购买的能量（千卡）、每天购买的总能量和收入。回归模型显示，在可用性干预期间，从干预类别购买的能源总体减少了 -4.8%（95% CI -7.0% 至 -2.7%），p < 0.001，减少了 -11.5%（95% CI -13.7） % 至 -9.3%），在可用性加规模干预期间，相对于基线，p < 0.001。 相对于单独的可用性而言，在可用性加规模期间，购买的能源减少了 -6.6%（95% CI -7.9% 至 -5.4%），p < 0.001。研究的局限性包括使用购买的能源作为主要结果（而不是消耗的能源）以及每个站点仅提供交易级销售数据（而不是个人级数据）。结论 减少食堂中高能量食品的比例可以减少购买的能量。减少份量进一步减少了这种情况。这些干预措施，特别是组合起来，可能会有效地作为减少户外环境中食物能量过度消耗的更广泛战略的一部分。试用注册 ISRCTN 注册表 ISRCTN87225572。